1. Field of the Invention
The invention relates to a gas-discharge lamp, more particularly to a glass tube lamp matrix device which has a longer useful life when compared to conventional gas-discharge lamps.
2. Description of the Related Art
Referring to FIG. 1, a conventional neon lamp 10 is shown to comprise a thin, generally U-shaped glass tube 12 and a pair of electrodes 14 disposed respectively at two sealed ends of the latter. The glass tube 12 is vacuumed before filling the same with an appropriate working gas, such as neon, in order to enable the lamp 10 to generate colored light when a predetermined voltage drop is applied between the electrodes 14. The electrodes 14 are connected to an external power source (not shown) by means of wires 140.
Some of the drawbacks of the conventional neon lamp 10 are as follows:
1. Because of the difficulty and high costs involved in vacuuming the glass tube 12 to near perfect levels, small amounts of impurities and other gases are usually retained in the tube 12. After prolonged use of the lamp 10 at high operating temperatures, a chemical reaction between the impurities inside the glass tube 12 and the electrodes 14 will occur, thereby resulting in corrosion and in a reduction in the amount of working gas. Sooner or later, because of an insufficient amount of remaining working gas, the lamp 10 would be useless due to its failure to emit sufficient light, thus resulting in a relatively short useful life for the lamp 10.
2. The glass tube 12 has an inner wall surface which is provided with a fluorescent substance layer. The conventional lamp 10 is similarly thrown away when the fluorescent substance layer fades due to prolonged use.
3. Too many accessories are required when the neon lamp 10 is installed in a lamp matrix used for advertising purposes, thereby resulting in a complicated assembly process and in higher costs for manufacturing the lamp matrix.